Our initial uncontrolled Stage Ia NIAAA funded treatment development project revealed not only promising findings, but the multiple substance using nature of the patient population in addition to the acceptability and feasibility of Mentorshp for Addiction Problems (MAP) for the treatment of substance use disorders. Thus, we now propose a Stage Ib randomized controlled pilot study to evaluate the preliminary efficacy of this approach with a broader group of substance abusers in response to PA-10- 013 issued by NIDA. MAP is a new behavioral intervention that formalizes client-to-client mentorship relationships as an adjunct to standard outpatient substance abuse (SA) treatment. Peer mentorship is a key component of many existing treatment/recovery approaches. Mentor training has tended to be informal not guided by standardized training manuals. Also, 12 Step approaches have been predominant in the U.S. and, while associated with improved outcomes, are not utilized by many patients, in part due to a religious emphasis on reliance on a higher power. MAP is based on Social Learning Theory and is designed to be compatible with a wide range of treatment philosophies to not only address substance abuse, but two significant problems in SA treatment: HIV/Infectious Disease risk behavior and attrition. While there has been a recent dramatic rise in the adoption of alternative forms of peer mentorship programs, most approaches have not been subjected to empirical efficacy testing. MAP is comprised of selection, training, and supervision procedures to enable successful recovering patients to serve as Mentors for clients who are early in the recovery process. Mentoring activities will revolve around assisting Mentees in progressing toward individualized treatment goals and entail 1 hour group mentoring and 1-4 hours of mentoring interaction within/outside of the treatment setting per week starting during the first 30 days of treatment when vulnerability to relapse and drop out is high. Mentors will be offered mentorship training consisting of 1 hour training sessions 2 times per week for 4 weeks prior to mentoring and supervision provided by professional staff in addition to providing the group and individual mentorship contact to the Mentee. 64 participants (16 Later Recovery Participants/LRP and 48 Early Recovery Participants/ERP) with substance use disorders will be randomized to MAP+TAU or TAU. For participants randomized to MAP, for each cohort, a pool of 4 Mentors will be formed and engage in mentoring activities for 24 weeks until 12 Mentees who are newly admitted have participated in MAP for 12 weeks. LRP must meet lifetime diagnosis for substance abuse or dependence and be 6 months abstinent from drugs and alcohol. ERP must meet current diagnosis for substance abuse or dependence and be actively using substances. Behavioral and biological measures will be conducted at baseline, weekly, monthly, and termination for all participants and during the 12 week follow-up for ERP.